Lithium and lithium ion batteries (collectively referred to herein as “lithium batteries”) are playing an increasingly important role as power sources for electronic devices and electric vehicles. The electrolytes currently used in lithium batteries can limit their efficiency, cost, cycling characteristics, and useful lifetime. A wide electrochemical window, wide temperature stability range, non-reactivity with the other cell components, non-toxicity, low cost, and a lithium-ion transference number approaching unity are, in general, desirable characteristics for lithium battery electrolytes. In addition, the electrolyte should have excellent ionic conductivity to enable rapid ion transport between the electrodes, and be an electronic insulator to minimize self-discharge and prevent short-circuits within the cell. Various carbonate solvents such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and mixtures of two or more of such carbonates, have been utilized as a solvent for lithium salts in lithium batteries and lithium-ion batteries.
Glycerol carbonate (GC) has been examined of use in electrolytes for lithium batteries (see co-pending application Ser. No. 12/910,549, filed Oct. 22, 2010, which is incorporated herein by reference in its entirety). While glycerol carbonate provides certain advantages when incorporated as a solvent or co-solvent in electrolyte formulations, the free hydroxyl group can be oxidized under cycling conditions, which can adversely affect cell performance.
There is an ongoing need for new electrolytes and functional electrolyte additives to improve cell life, thermal abuse behavior and low-temperature (e.g., <0° C.) performance of lithium-ion cells. The present invention addresses this need.